Discharge device



June 9, 1964 w. F. BELTZ ETAL 3,136,027

DISCHARGE DEVICE Filed July 14. 1961 m Aw;

Z INVENTORS W/u/s f. 55.4725

BY 7 10,144.; J HOWE Arron 5r United States Patent a corporation of Delaware Filed July 14, 1961, Ser. No. 124,224 4 Claims. (Cl. 29-2514) Our present invention relates to magnetrons and particularly concerns an improved vane type magnetron anode and novel method of making the same.

1 Vane type magnetron anodes of the flat vane type have heretofore comprised a plurality of separate parts mutually fixed by suitable means such as brazing. The parts comprise an anode block made of a metal such as copper and having a circular opening extending therethrough. A plurality of fiat vanes are fixed to the wall of the opening and extend radially towards the center of the opening, the free ends of the vanes defining a cylindrical space for receiving one or more other electrodes. The vanes are often provided with notches or indentations in the side edges thereof to receive so-called straps. The notches are differently shaped in adjacent ones of the vanes, alternate vanes having similarly shaped notches.

Several problems are associated with magnetron anodes having the structure described. These problems arise as a consequence of the need heretofore of utilizing separate parts for the several portions of the anode. The use of separate parts involves troublesome features such as the requirement for extremely close tolerances which not only increase the cost of the parts but render the assembling operation diflicult and time consuming. Furthermore, the use of separate parts require a fixing, for example, by a-solder, which lowers circuit efiiciencies and adversely affects the performance of a magnetron in which such parts are used. The fixing means heretofore was often limited to solder because other means, could not be tolerated for various reasons, for example, welding could not be tolerated because of the precise spacings re quired. But solder, in addition to its adverse circuit effects referred to, is inherently inadequate for precision assemblies of the type involved in magnetron anodes. This inadequacy has heretofore manifested itself in the need to frequently resolder previously soldered faulty joints. This resoldering requirement has adversely affected the yield of prior anode assembling operations and has added appreciably to the cost of the finished product.

The prior need to use separate parts for the anode assembly was dictated primarily by the requirement for indentations or notches of different contour in adjacent vanes, for receiving straps in such fashionthat each strap engages alternate ones only, of the vanes. This difference in indentation in adjacent vanes precluded the formation of the indentations or notches in the vanes by turning in a lathe, or by any other technique consistent with the high degree of precision required. In view of this problem it Was not consideredfeasible heretofore to form into an integral structure, the block and flat vanes of a magnetron anode of the type discussed.

An important object of the invention therefore, is to provide a magnetron anode of the fiat vane type in which the vanes thereof are integral with the anode block, and in which adjacent vanes have precision made differently shaped notches for accommodating suitable strapping means.

Another object is to provide an improved method of making a flat vane type magnetron anode.

According to a structural feature of the invention, the block of a magnetron anode of the flat vane type including the vanes thereof suitably notched, constitute one integral structure having important advantages in the circuit in which the structure is used. The one piece structure also contributes to economy in fabricating a magnetron anode, thereby contributing to a reduction in cost of the completed magnetron device.

According to a method feature of the invention, a magnetron anode blank made of a coinable metal such as copper, is subjected to a coining operation in a face thereof to provide desired notches or indentations therein arrayed in a circular pattern in areas that will eventually constitute side edges of vane portions of the completed anode block. The coining operation may be performed by a coining tool adapted to imprint in a face of the blank in one step, all the indentations required to provide the desired vane indentations in such face.

According to a preferred method, the indentations are coined in the anode blank prior to the formation of vanes in the blank. In this way, any upset material adjacent to the indentations may be conveniently removed in a following step of removing, as by broaching, the material of the blank between the desired vanes.

Further objects and features of the invention will become evident from the following detailed description of an illustrative embodiment, taken in connection with the accompanying drawing, wherein FIG. 1 is a fragmentary plan view of a magnetron anode embodying the invention;

FIG. 2 is an enlarged sectional view taken along the line 2-2 of FIG. 1;

FIG. 3 is a plan view of an anode blank to be subjected to the method of the invention;

FIG. 4 is a sectional view taken along the line 4-4 of FIG. 3;

' FIG. 5 is a plan view of the blank shown in FIG. 3 after it has been subjected to a coining step in accordance with the invention;

FIG. 6 is a sectional view along the line 66 of FIG. 5 and through the region of coined indentations in opposite faces of the anode blank;

FIG. 7 is a sectional plan view of a broaching tool useful in removing material of the anode blank between the indentations shown in FIG. 5 and between the desired vanes in the completed anode structure; and

FIG. 8 is a plan view of the processed anode blank showing vanes and having indentations in the side edges of the vanes integral with a block.

A more detailed consideration of the drawing will reveal in FIGS. 1 and Zthereof, a completed vane type magnetron anode according to the invention. The anode there shown comprises a block 10 having a recessed portion 12 and flat vanes 14 integral with the block. Each.

of the straps is to electrically interconnect alternate ones of the vanes provided in the side edges referred to.

For example, and as shown in FIG. 1, ring-strap 16 engages vanes 14 and 26 and is free from contact with vanes 28 and 30, while ring-strap 18 engages vanes 28 and 30 and is free from contact with vanes 14 and 26. Furthermore, and as shown in FIG. 2, opposite side edges 32, 34 of each vane, (vane 28 being shown) engage alternate ones of the straps referred to. Thus, edge 32 contacts strap 18, while strap 16 is free from such edge contact, and edge 34 engages strap 20, while strap 22 is free from engagement with this edge. The straps are suitably fixed to the vanes they contact, as by means of solder.

To provide the structure shown in FIGS. 1 and 2, one step comprises forming or coining indentations or notches, 38, 40 in the anode blank, as shown in FIGS. 5 and 6. Notches 38 are provided in one face of the blank 36 while notches 40 are formed in the opposite face of the blank.

Patented June 9, 1964 The notches in each face of the blank are disposed in a circular array and in regions that will eventually constitute side edges of vanes. ternate notches in each face have similar configurations, so that one portion or step 42 engages in electrical contact relation a ring-strap aforementioned and another portion 44 of greater depth than step 42, provides electrically insulating clearance for another ring-strap. Notches 40 in the opposite face of the blank 36 are so shaped that step portion 46 thereof is opposite the deep portion 44 of notches 38 and the deep portion 48 of notches 40 is opposite the step portion 42 of notches 38.

To provide the notches referred to, a coining tool (not shown) is utilized. The coining tool is provided with a work face having projections extending therefrom, shaped to provide the notches referred to when the work face is forcefully urged against a face of the blank 36. The coining tool is made of a hard metal, such as hardened steel, so as to facilitate the coining of notches in the anode blank. The blank is made of a relatively soft metal, such as copper, for appropriate response in notch formation therein, to a forced application thereto of the coining tool. In forming the notches in the two opposite faces of the blank 36 in two successive operations, the coining tool should be rotated about the center of opening 50 in the blank, a distance equal to the spacing between adjacent notch-forming projections on the tool, between the two operations, to provide the staggered notch arrays in the two blank faces, as shown in FIG. 6.

To provide the vanes 52 (FIG. 8) integral with the anode block 10, the material in the spaces 54 between eventual adjacent vanes, is removed in a suitable manner. One way in which the removal of material may be effected is by the use of a broaching tool 56 shown in FIG. 7. The breaching tool includes a base 58 from which extend a plurality of fingers 60 and 62 having a length sufficient to penetrate the block in the offset region 12 thereof. Finger 60 has a shape not only to remove the material between vanes 64, 66 but also to remove material in the block 10 to provide a slot 68. In one method of removal, the breaching tool 58 may constitute an electrode maintained at a different electrical potential from the anode blank 36. When the free ends of the fingers 60, 62 of the tool are brought sufficiently close to the-anode blank, a series of electrical discharges between the fingers and the anode blank, will erode the material of the blank adjacent to the fingers to form the spaces 54 and slot 63 in the blank, having shapes determined by the shapes of the fingers. This is a form of electrical discharge machining known in the art. Removal of the material between the vanes of the blank may also be effected by mechanical breaching, which is generally known and therefore requires no further description herein.

The coining operation for providing the notches or indentations 38, 40, may be performed after or prior to the removal of material from the spaces 54 to provide the vanes 52. It is preferred, however, to remove the material between adjacent eventual vanes after the notches 38, 40 have been formed in the blank. This preference is dictated by the fact that formation of the notches 38, 40 involves some upset of the adjacent material of the blank, when the notching operation is performed prior to material removal, and some deformation or burr formation in the vanes is likely to be left if the coining is carried out after the vanes have been isolated from the adjacent material of the blank. The material in the upset regions is automatically removed when the coining operation precedes the material removal step, whereas, the burr formations occurring when the coining is deferred until the vanes have been formed, persist and require an additional and time consuming step in removal.

It is apparent from the foregoing that we have provided an improved magnetron anode structure. Furthermore, an improved method of making a magnetron has been described that not only is characterized by economy but in improved precision. This improved precision is superior to that realized by the use of jigs, as heretofore, and contributes appreciably to the fabrication of a magnetron having superior operating characteristics.

We claim:

1. Method of making a magnetron anode of the fiat vane type from a metallic block having a circular opening extending therethrough, comprising the steps of coining depressions in said block in an array concentric with said opening, and in which said depressions are uniformly spaced, removing the material of said block between said depressions to form a plurality of vanes extending radially towards said opening and having said depressions in the edges thereof, fixing a first ring shaped metal strap to alternate ones only, of said vanes and in said depressions therein, and fixing a second ring to the remaining vanes only, and in said depressions therein.

2. Method of making a magnetron anode of the fiat vane type, comprising forming depressions in a radial array in a face of a metal work piece having an opening therethrough, and removing the material of said work piece between said depressions to form vanes extending to said opening and integral with said work piece and having said depressions in side edges thereof, and mounting ring shaped straps in said depressions.

3. In a method of making a magnetron anode, the steps comprising coining depressions in selected areas of one face of a coinable work piece, and removing the material of said work between said selected areas.

4. Method of making a magnetron anode of the flat vane type, comprising coining notches in selected circularly arrayed areas of one face of a coinable metallic Work piece, whereby the material of said work piece is upset in other areas of said face adjacent to said selected areas, removing the material between said selected areas and including said other areas for forming radially extending flat vanes integral with said work piece and having said notches in side edges thereof, and mounting metallic rings in said notches electrically interconnecting alternate ones of said vanes only.

References Cited in the file of this patent UNITED STATES PATENTS 2,645,843 .Nordsieck July 21, 1953 2,784,480 Goddard a Mar. 12, 1957 2,906,921 Gardiner Sept. 29, 1959 2,950,416 Brown Aug. 23, 1960 3,058,029 Clampitt Oct. 9, 1962 

1. METHOD OF MAKING A MAGNETRON ANODE OF THE FLAT VANE TYPE FROM A METALLIC BLOCK HAVING A CIRCULAR OPENING EXTENDING THERETHROUGH, COMPRISING THE STEPS OF COINING DEPRESSIONS IN SAID BLOCK IN AN ARRAY CONCENTRIC WITH SAID OPENING, AND IN WHICH SAID DEPRESSIONS ARE UNIFORMLY SPACED, REMOVING THE MATERIAL OF SAID BLOCK BETWEEN SAID DEPRESSIONS TO FORM A PLURALITY OF VANES EXTENDING RADIALLY TOWARDS SAID OPENING AND HAVING SAID DEPRESSIONS IN THE EDGES THEREOF, FIXING A FIRST RING SHAPED METAL STRAP 